A zone-selective-interlocking system for an electrical power distribution system that has at least one upstream breaker and at least one downstream breaker is provided. Each breaker in the power distribution system has a zone-selective-interlocking circuit that includes a zone-selective-interlocking-input circuit and a zone-selective-output circuit. The zone-selective-interlocking system also includes a monitoring device to monitor the voltage sent from the zone-selective-interlocking-output circuit of the at least one downstream breaker to the zone-selective-interlocking-input circuit of the at least one upstream breaker and determine whether there is a proper or improper connection between the upstream and downstream breaker and whether the downstream breaker is sending a restraint signal to the upstream breaker.
|
16. A method of verifying a connection between at least one upstream breaker and at least one downstream breaker in a power distribution system comprising the steps of:
providing a zone-selective-interlocking system connected to the upstream breaker and the downstream breaker;
determining, by the downstream breaker, if a controller setting associated with an output of a zone-selective-interlocking circuit at the downstream breaker is set to an ON state;
measuring, by the downstream breaker, a zone-selective-interlocking system signal at the output;
determining, by the downstream breaker, that there is an open connection between the upstream breaker and the downstream breaker based on a result of the step of measuring when the controller setting is set to the ON state; and
effecting an alarm if there is an open connection thereby informing an operator of the open connection.
10. A zone-selective-interlocking system for an electrical power distribution system having at least one upstream breaker and at least one downstream breaker comprising:
a zone-selective-interlocking circuit connected to the at least one upstream breaker and the at least one downstream breaker; and
a monitoring portion to verify the connection of the zone-selective-interlocking circuit to the at least one upstream breaker and the at least one downstream breaker,
wherein the zone-selective-interlocking circuit further includes a zone-selective-interlocking-input circuit at the upstream breaker and a zone-selective-interlocking-output circuit at the downstream breaker, and wherein the monitoring portion further includes a self-test portion, wherein the self-test portion measures a signal sent from the zone-selective-interlocking-output circuit of the at least one downstream breaker to the zone-selective-interlocking-input circuit of the at least one upstream breaker.
20. A zone-selective-interlocking (zsi) system in an electrical power distribution system comprising an upstream breaker and a downstream breaker, the zsi system comprising:
a zsi circuit connected to the upstream breaker and the downstream breaker; and
a monitoring portion of the upstream breaker to verify the connection of the zsi circuit to the upstream breaker and the downstream breaker,
wherein the monitoring portion of the upstream breaker monitors a zsi signal input of the upstream breaker, and determines that an open circuit condition exists between the upstream breaker and the downstream breaker in the zsi circuit based a first signal condition of the zsi signal input, determines that a proper connection condition exists between the upstream breaker and the downstream breaker in the zsi circuit based on a second signal condition of the zsi signal input that is different from the first signal condition, and determines that both of a restraint signal is sent from the downstream breaker to the upstream breaker and that said proper connection condition exists based on a third signal condition of the zsi signal input that is different from the first and second signal conditions.
18. A method of verifying a connection between at least one upstream breaker and at least one downstream breaker in a power distribution system comprising the steps of:
providing a zone-selective-interlocking system connected to the at least one upstream breaker and the at least one downstream breaker;
determining if an input or output of a zone-selective-interlocking circuit at the downstream breaker is set to an ON position;
measuring a zone-selective-interlocking system signal at the input or output;
determining if there is an open connection between the at least one upstream breaker and the at least one downstream breaker based on the determining and measuring step results; and
effecting an alarm if there is an open connection thereby informing an operator of the open connection, wherein after the step of determining if there is an open connection between the at least one upstream breaker and the at least one downstream breaker if there is not an open connection the method further comprising the steps of determining if there is a restraint signal sent from a zone-selective-interlocking-output circuit of the at least one downstream breaker to a zone-selective-interlocking-input circuit of the at least one upstream breaker and setting the at least one upstream breaker to trip at normal GF and ST time-delay-trip settings if a restraint signal is determined.
1. A zone-selective-interlocking (zsi) system for an electrical power distribution system having at least one upstream breaker and at least one downstream breaker comprising:
a zone-selective-interlocking circuit connected to the at least one upstream breaker and the at least one downstream breaker; and
a monitoring portion of the at least one upstream breaker to verify the connection of the zone-selective-interlocking circuit to the at least one upstream breaker and the at least one downstream breaker,
wherein the monitoring portion of the at least one upstream breaker measures a signal level of a zsi signal input of the at least one upstream breaker, and determines that an open circuit condition exists between the at least one upstream breaker and the at least one downstream breaker in the zone-selective-interlocking circuit based a measured first signal level of the zsi signal input, determines that a proper connection condition exists between the at least one upstream breaker and the at least one downstream breaker in the zone-selective-interlocking circuit based on a measured second signal level of the zsi signal input, and determines that both of a restraint signal is sent from the at least one downstream breaker to the at least one upstream breaker and that said proper connection condition exists based on a measured third signal level of the zsi signal input.
2. The zone-selective-interlocking system of
3. The zone-selective-interlocking system of claim l, wherein the monitoring portion effects an alarm based on the measured first signal level.
4. The zone-selective-interlocking system of
5. The zone-selective-interlocking system of
6. The zone-selective-interlocking system of
7. The zone-selective-interlocking system of
8. The zone-selective-interlocking system of
9. The zone-selective-interlocking system of
wherein the controller includes respective ON and OFF settings associated with each of the zsi signal input and the zsi signal output, and
wherein an alarm of the at least one upstream breaker is inactive when at least one of the settings is set to OFF.
11. The zone-selective-interlocking system of
12. The zone-selective-interlocking system of
13. The zone-selective-interlocking system of
14. The zone-selective-interlocking system of
15. The zone-selective-interlocking system of
wherein the controller includes respective ON and OFF settings associated with each of the zone-selective-interlocking-input circuit of the at least one upstream breaker and the zsi signal output of the at least one upstream breaker, and
wherein an alarm of the at least one upstream breaker is inactive when at least one of the settings is set to OFF.
17. The method of
19. The method of
ignoring the GF and ST time-delay-trip settings of the at least one upstream breaker if a restraint signal is not determined.
21. The zone-selective-interlocking system of
22. The zone-selective-interlocking system of
wherein the controller includes respective ON and OFF settings associated with each of the zsi signal input and the zsi signal output, and
wherein an alarm of the upstream breaker is inactive when at least one of the settings is set to OFF.
|
The present invention relates to circuit breaker protection in the electrical power distribution industry and more specifically to a zone selective interlocking system having a signal-monitoring system to verify the interconnection of upstream and downstream circuit breakers.
Zone selective interlocking (ZSI) systems have been available in the electrical power distribution industry for many years. The standard electrical power system protection provides selective-protective coordination between an upstream (main) breaker and the downstream (feeder) breakers. Thus, in the event of a fault (e.g. a short circuit, ground fault or an overload) the standard protection system selectively coordinates the upstream and downstream breakers so that the nearest downstream breaker will clear the fault before the upstream breaker opens. Therefore, because a downstream breaker nearest to the fault clears the fault a minimal number of feeders are de-energized.
Selective-protective coordination between upstream and downstream breakers is achieved by adding an additional time delay to the trip unit of the upstream breaker to thereby give the downstream breaker time to interrupt the fault. The ZSI system adds to the standard selective-protective coordinated system by allowing the upstream breaker to identify a fault within its zone (ahead of the feeder breakers) and clear this fault without adding the time delay required by selective-protection coordination. More specifically in a selectively coordinated protective system with ZSI, when a downstream breaker detects a current greater than its ground fault (GF) pick-up, short time (ST) pick-up or its instantaneous (I) pick-up it will send a restraint signal back to the upstream breaker. The upstream breaker, upon seeing the restraint signal, will begin to time out based on its normal selective-coordination GF or ST time-delay-trip setting. In a first scenario, if the downstream breaker operates properly it will trip thereby clearing the fault. Further, the upstream breaker will stop timing its GF or ST time-delay-trip setting and, thus, will not trip. In this first scenario, the downstream breaker cleared the fault and a minimal number of feeders were affected. In a second scenario, if the downstream breaker detects the fault and sends a restraint signal to the upstream breaker but the downstream breaker does not operate properly to clear the fault the GF or ST time-delay-trip setting on the upstream breaker will time out and the upstream breaker will trip thereby clearing the fault. Thus, the upstream breaker acts as a back up breaker to the downstream breaker in the event that the downstream breaker does not operate properly. In this second scenario, however, all feeders downstream from the tripped upstream breaker are de-energized. In a third scenario, if the upstream breaker with ZSI detects a GF or ST fault and does not receive a ZSI restraint signal from a downstream breaker, the upstream breaker will assume that the fault is in its protection zone (ahead of the feeder breakers) and will ignore its GF or ST time-delay-trip settings and will trip with minimal time delay thereby quickly clearing the fault. In this third scenario, if the ZSI signal connection between the downstream breaker and the upstream breaker were improperly connected, damaged or somehow malfunctioning, the upstream breaker would never receive a restraint signal and would always consider a fault to be within its zone and trip without a time delay on a GF or ST fault even if a downstream breaker was also in the process of clearing the fault. The improper or damaged ZSI signal connection, however, would not be detected until a fault occurred and the upstream breaker tripped with minimal delay thereby not only clearing the fault but also de-energizing all downstream feeders connected to the upstream breaker. In this scenario the selective-protective coordination of the power distribution system is totally lost. Thus, what is required is a ZSI system with a monitoring system to verify the ZSI signal interconnection between the upstream and downstream breakers that will: 1) override the non-coordination function of an upstream breaker in a ZSI system and 2) create an error message and alarm in the event of an improper or damaged ZSI signal connection between the upstream and downstream breakers.
In accordance with one aspect, a zone-selective-interlocking system for an electrical power distribution system has at least one upstream breaker and at least one downstream breaker. A zone-selective-interlocking circuit is connected to the at least one upstream breaker and the at least one downstream breaker. A monitoring portion verifies the connection of the zone-selective-interlocking circuit to the at least one upstream breaker and the at least one downstream breaker.
In accordance with another aspect, a method of verifying a connection between at least one upstream breaker and at least one downstream breaker in a power distribution system includes the steps of providing a zone-selective-interlocking system connected to the at least one upstream breaker and the at least one downstream breaker; determining if an input or output of a zone-selective-interlocking circuit at the downstream breaker is set to an ON position; measuring a ZSI signal at the input or output; determining if there is an open connection between the at least one upstream breaker and the at least one downstream breaker based on the determining and measuring step results; and effecting an alarm if there is an open connection thereby informing an operator of the open connection.
Additional features, benefits or advantages of the present invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification.
The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings that form a part of the specification.
The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings that form a part of the specification.
Referring now to the drawings,
Referring to
Each ZSI-input circuit 22 has two ZSI-input terminals I, C and each ZSI-output circuit 24 has two ZSI-output terminals O, C, where C designates common. The ZSI-output terminals O, C of each of the downstream breakers are connected in parallel to the ZSI-input terminals I, C of its corresponding upstream breaker(s), as shown in
Referring to
Referring to
Referring to
If the downstream voltage as seen at the input terminals I, C of the ZSI circuit 20 of the upstream breaker is, for example, approximately 15V, which produces a logic “1” on input IN1 to the controller 28, then this breaker is an upstream breaker for a zone and at least one downstream breaker is properly connected. The 15V is generated from the Zener diode D1 located in the ZSI-output circuit 24 of the downstream breaker(s). When properly connected, the Zener diode D1 of the downstream breaker pulls the ZSI-input voltage of the upstream breaker down to 15V.
If the downstream voltage as seen at the input terminals I, C of the ZSI circuit 20 of the upstream breaker is, for example, approximately 6V, which produces a logic “1” on input IN2 to the controller 28, then this breaker is an upstream breaker for a zone and at least one downstream breaker has detected a fault and this downstream breaker is sending a restraint signal to the upstream breaker. In this case, the controller 28 in the downstream breaker that has detected the fault turns on the optically isolated transistor T2, via port OUT1, which turns on transistor T1 that pulls down its ZSI-output voltage to approximately 6V. Thus, the upstream breaker will time out based on its GF or ST time-delay-trip setting thereby giving the downstream breaker the time to clear the fault.
If the ZSI voltage as seen at the output terminals O, C of the ZSI circuit 20 of the downstream breaker is, for example, greater than approximately 2.5V then there is a good electrical connection between the upstream breaker and the downstream breaker and the ZSI circuit 24 of the downstream breaker produces a logic “0” on input IN3 to the controller 28.
If the ZSI voltage as seen at the output terminals of the ZSI circuit 20 of the downstream breaker is, for example, approximately 0V then either, 1) there is no upstream breaker and the ZSI-output is set to OFF (see, for example, breaker A in
While specific embodiments of the invention have been described and illustrated, it is to be understood that these embodiments are provided by way of example only and that the invention is not to be construed as being limited thereto but only by proper scope of the following claims.
Weiher, Helmut, Patterson, Jeffrey W., Fleischer, Richard C.
Patent | Priority | Assignee | Title |
10444725, | Feb 22 2017 | ABB S P A | Power distribution systems and methods of performing zone selective interlocking in power distribution systems with a communication network |
10644498, | Feb 22 2017 | ABB Schweiz AG | Power distribution systems and methods of performing zone selective interlocking in power distribution systems with a communication network |
10673226, | Feb 22 2017 | ABB S P A | Power distribution systems and methods of operating power distribution systems with a communication network |
10797479, | Feb 22 2017 | ABB S P A | Power distribution systems and methods of performing ground fault detection in power distribution systems with a communication network |
10935604, | Feb 22 2017 | ABB S P A | Power distribution systems and methods of testing responses to electrical conditions using a communication network |
8144442, | Jul 03 2008 | GOOGLE LLC | Power protection in a multi-level power hierarchy |
9564751, | Nov 14 2014 | ABB S P A | Zone selective interlocking and circuit protection device monitoring in a power distribution system |
9692223, | Oct 31 2013 | ABB S P A | Power distribution systems and methods of testing a power distribution system |
9692224, | Jun 15 2015 | ABB S P A | Power distribution systems and methods of monitoring zone selective interlocking in a power distribution system |
9728955, | Dec 11 2013 | ABB S P A | Zone selective interlocking (ZSI) power distribution operating a ZSI power distribution system |
9837812, | Nov 20 2014 | ABB S P A | Power distribution systems and methods of operating power distribution systems with partial differential protection |
Patent | Priority | Assignee | Title |
4271444, | Jul 31 1979 | General Electric Company | Ground fault trip mode network for static trip circuit breakers |
4464697, | Jul 13 1982 | ABB POWER T&D COMPANY, INC , A DE CORP | Protective relay system |
4468714, | Nov 01 1982 | General Electric Company | Zone selective interlock module for use with static trip circuit breakers |
4689708, | Aug 02 1985 | BBC BROWN, BOVERI & COMPANY LIMITED, A CORP OF SWITZERLAND | Zone protective directional relay scheme |
4706155, | Mar 06 1985 | Square D Company | Restraint signal interface circuit |
4791520, | Mar 08 1986 | Sachsenwerk Aktiengesellschaft | Fault protection for a medium voltage transformer branch |
4896241, | Feb 28 1989 | ABB POWER T&D COMPANY, INC , A DE CORP | Directional comparison blocking protective relay system |
4996646, | Mar 31 1988 | SQUARE D COMPANY, A CORP OF MI | Microprocessor-controlled circuit breaker and system |
6160690, | Oct 30 1998 | Mitsubishi Denki Kabushiki Kaisha | Distribution control system and distribution control method capable of isolating fault section without fail |
6297939, | Nov 05 1999 | SIEMENS INDUSTRY, INC | Zone selective interlock for a circuit breaker system |
6313975, | May 08 1998 | Square D Company | Self-sourcing, isolated zone selective interlocking system for use with electronic trip circuit breakers |
6356422, | Nov 05 1999 | SIEMENS INDUSTRY, INC | Circuit breaker communication and control system |
6369995, | Jan 08 1999 | Mitsubishi Denki Kabushiki Kaisha | Protection relay device for distribution equipment |
6714395, | Jun 30 2000 | S & C ELECTRIC CO | Method for detecting faults internal to a distribution equipment configuration |
7196884, | Mar 02 2005 | Schweitzer Engineering Laboratories, Inc.; Schweitzer Engineering Laboratories, Inc | Apparatus and method for detecting the loss of a current transformer connection coupling a current differential relay to an element of a power system |
20030231440, | |||
20040130837, | |||
20040130838, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Feb 15 2007 | WEIHER, HELMUT | Utility Relay Company | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 018903 | 0922 | |
Feb 15 2007 | PATTERSON, JEFFREY W | Utility Relay Company | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 018903 | 0922 | |
Feb 15 2007 | FLEISCHER, RICHARD C | Utility Relay Company | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 018903 | 0922 | |
Feb 20 2007 | Utility Relay Company | (assignment on the face of the patent) | ||||
Sep 02 2010 | UTILITY RELAY CO , LTD | Fifth Third Bank | SECURITY AGREEMENT SENIOR DEBT | 024964 | 0285 | |
Sep 02 2010 | UTILITY RELAY CO , LTD | Fifth Third Bank | SECURITY AGREEMENT SENIOR SUBORDINATED DEBT | 024964 | 0681 |
Date | Maintenance Fee Events |
Jul 21 2009 | ASPN: Payor Number Assigned. |
Jan 21 2013 | M2551: Payment of Maintenance Fee, 4th Yr, Small Entity. |
Jan 18 2017 | M2552: Payment of Maintenance Fee, 8th Yr, Small Entity. |
Nov 12 2020 | M2553: Payment of Maintenance Fee, 12th Yr, Small Entity. |
Date | Maintenance Schedule |
Aug 04 2012 | 4 years fee payment window open |
Feb 04 2013 | 6 months grace period start (w surcharge) |
Aug 04 2013 | patent expiry (for year 4) |
Aug 04 2015 | 2 years to revive unintentionally abandoned end. (for year 4) |
Aug 04 2016 | 8 years fee payment window open |
Feb 04 2017 | 6 months grace period start (w surcharge) |
Aug 04 2017 | patent expiry (for year 8) |
Aug 04 2019 | 2 years to revive unintentionally abandoned end. (for year 8) |
Aug 04 2020 | 12 years fee payment window open |
Feb 04 2021 | 6 months grace period start (w surcharge) |
Aug 04 2021 | patent expiry (for year 12) |
Aug 04 2023 | 2 years to revive unintentionally abandoned end. (for year 12) |